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(No Model.)

G. M. HOPKINS. Telegraph Relay.

No. 237,185. Patented Feb. 1,1881.

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W e Z a? l I c VII 12/ J4 j I? 6 L ff ll fi a F/y g i a L I j] lWITNESSES:

UNITED STATES PATENT OFFICEO GEORGE M. HOPKINS, OF BROOKLYN, NEW YORK.

TELEGRAPH-RELAY.

SPECIFICATION forming part of Letters Patent No. 237,185, dated February1, 1881.

Application filed July 10, 1880. (No model.)

To all whom it may concern Be it known that I, GEORGE M. HOPKINs, ot'Brooklyn, in the county of Kings and State of New York, have invented anew and useful Improvement in Telegraph-Relays and I do hereby declarethat the following is a full, clear, and exact description of the same,ref erence being had to the annexed drawings, forming a part of thisspecification, in which- Figures 1 and 2 represent different forms of myinvention. Fig. 3 is a detail view of the movable contact-surface, andFig. at is a detail view of the auxiliary heating apparatus.

My present invention is an improvementon a telegraph-relay on whichLetters PatentNo. 229,414 were granted to me June 29, 1880.

The improvement consists, first, in novel mechanism for utilizing thevariable expansion of an electrical conductor, forming a portion of themain telegraph-line; second, in a device for augmenting the expansion ofthe electrical conductor by the application of external heat; third, ina movable contact-surface operated by suitable power for prevent-in gthe sticking or welding of the local-circuit contact-surfaces; and,fourth, in a sliding contact for putting more or less of the expansibleconductor under the influence of the current.

The expansion-wire Ais attached at one end to an adjustable hook, a,supported in the binding-post b, and held in any desired position by aset-screw, c. The other end of the expansion-wire A is received by oneend of a double connecting-hook, B, attached by insulators d to anapertured plate, 0. The other end of the double hook is connected, by ashort spiral spring, 0, with an adjustable hook,f, in the binding-postD.

An arbor, E, supported by delicate pivots. carries an arm, F, which ispreferably made of aluminum, that metal being very light, and at thesame time a good conductor of electricity. The free end of the arm F isprovided with a platinum point, g, which is capable of touching arotative platinum-faced disk, h, above or below the center of the disk.This relative arrangement of parts secures a line of thrust at rightangles with the axial line of the arbor E, and prevents bending thelever 1' when the platinum point 9 is pressed against the platinum-faceddisk h. The object of employing a movable contact-surface, which, in thepresent case, is the rotative disk h, is to avoid the sticking orwelding of the contactsurfaces together by the discharge of the extracurrent from the localsounder magnet by constant movement of one of thesurfaces at right angles to the plane of motion of the othercontact-surface.

Fig. 3 is a side elevation, showing the rela tive positions of thecenters of the contactsurfaces 9 h, and also of the insulated screw 1',which arrests the retrograde moveinentof the lever F.

The disk It may be revolved by a small electric motor, by clock-work, orin any other convenient and desirable way. The power will be applied toits shaft. A slow speed will suftice.

On the arbor is placed a V-shaped metallic friction-piece, Gr, having onits extremities hooks k l. The hook it enters an aperture in the plate0, and the hook 1 receives an adjustable spring, 122, by which thefriction-piece G is brought into light contact with the arbor E.

A metallic bar, H, arranged parallel to the expansion-wire A, supports aslide, I, carrying a platinum finger, a, over which the wire A isstretched. The bar H is electrically connected with the post I), so thatwhen the expansion wire A is thrown into the main line, by connectingthe posts b D with the main-line wires, the greater portion of thecurrent will pass from the post b, through the bar H, slide I, andfinger a, before passing over the working portion of the wire A, so thatby moving the slide 1 more or less of the expansion-wire A may be throwninto the circuit, thus adapting the length of the expansion-wire to thestrength of the current passing over the line.

When very feeble currents are employed to work the relay thesensitiveness of the expansion-wire is increased by using artificialheat. The manner in which this is done is clearly shown in Fig. 4.

A plate, K, of copper or othersuitable metal, is supported a shortdistance below the expansion-wire, and below the plate are placed two orthree very small gas-jets, 0, which heat the plate K, and the lattersupplies the initial heat to the wire A, increases the electricalresistance of the wire A, and renders it more sensitive to slightcurrents.

When an electrical impulse is sent through 5 a telegraph-line of whichthe expansion-wire A forms a part, the wire is expanded more or less,according to the strength of the current, and the pressure on the hookit of the frictionpieoe G being relieved, the latter is drawn around bythe spring on. The friction between the piece G and the arbor E issufficient to cause the arbor to turn with the friction-piece carryingthe lever F until the contact-point g strikes the disk It. If the wire Acontinues to expand after the contact of the point 9 with the disk It,the friction-piece G moves forward on the arbor E without producing anyeffect. When the main-line circuit is opened the wire A immediatelycontracts, and, by pulling the hook I, first turns the arbor E, movingthe lever F, until the contact between the point 9 v and disk It isbroken and the back of the lever F touches the screw 2'. Should the wirecontract still further the only effect produced is to move thefriction-piece G around on the arbor E.

The wires of the local circuit are connected with the bearings of thedisk h and pivots of the arbor E, so that the local-battery currentpasses through the arbor E, lever F, platinum point g, disk It and itsbearin gs, and the sounder.

The wire used in the relay should be of platinum of about 10300 to of aninch in diameter. As wire as fine as this is liable to accidentalbreakage, I have added'to the instrument already described a device forcompleting the main-line circuit automatically in case of the breakageof the expansion-wire A. This device consists of two platinum pins, 1)placed on opposite sides of the hook B and connected electrically withthe bar H. A cross-piece, q, also of platinum, is secured to the-hook Ba short distance from thepins pp, 45 so that should the expansion-wire Abreak,

the spring 0 will carry the bar (1 against the pins 19 p and completethe main-line circuit.

Fig. 2 shows a method of compounding levers so as to increase the motionof the lever F. In this figure parts that are found in Fig. 1 will beindicated by the sameiletters of reference. In this case an auxiliarylever, L, is pivoted in the same frame with the lever F, and isconnected at its free end with the friction-piece G by a link. Theexpansion-wire A is connected with the lever L by a link, a", and iskept under tension by the spring 0 on the opposite side of the lever.Every motion of the expansion-wire is multiplied by the lever L, andagain by the lever F. The platinum pin p,whichis connected electricallywith the bar H, is touched by the lever L, completing the main-linecircuit, in case of the breakage or disconnection of the expansion-wire.

Having thus described my invention, I claim 1. In a telegraph-relay, thecombination of the expansion-wire A, frictioirpiece G, spring m, andarbor E, as shown and described.

2. The method of augmenting the expansion of an electricalconducting-wire by the application ot'extern al h eat, as hereinspecified.

3. In a telegraph-relay, the combination of a heater with anexpansion-wire, as specified.

4. In a telegraph-relay, a rotative contactsurface, in combination witha vibratory contact-surface, substantially as specified.

5. In a telegraph-relay, a movable electrical conductor, in combinationwith the expansionwire, for putting moreorless of the expansionwire intocircuit, as specified.

6. In a telegraph-relay, the contact-pins 19,- electrically connectedwith the main line, and the movable contact-bar q, connected with themain line, in combination with the expansion- 85 wire A and spring 6, asherein specified.

GEO. M. HOPKINS.

I/Vitnesses:

G. SEDGWIOK, O. L. TOPLIFF.

